1. Field of the Invention
The present invention relates to an iron golf club and an iron golf club set including the same, particularly to an iron golf club having a head body of light metal such as titanium or titanium alloy, and weight members disposed in the head body, the weight members being formed of material having a specific weight heavier than the aforesaid light metal, and an iron golf club set including the same.
2. Description of the Related Art
Conventional iron golf clubs are known to have a head body formed of a light metal such as titanium alloy, pure titanium, or aluminum, and a weight member disposed below a cavity provided at a rear surface of the head body. The weight member is typically a block made of beryllium--copper alloy, copper alloy, or stainless steel, the block material having a specific gravity which is heavier than the light metal utilized for the head body.
Iron clubs of this type are designed to provide specific dynamic characteristics which result from lowering the center of gravity of the club head. More specifically, the above characteristics include the following:
(a) a more effective swing due to a shift of the center of gravity of the club head to a lower rear portion of the head; and PA1 (b) a higher ball trajectory to attain a longer distance.
The center of gravity of the aforesaid iron golf club head, however, is positioned at a lower central portion of the head. This is because a one-piece weight member is employed and disposed along the lower portion of the rear cavity of the head from the heel to the toe side, thus locating the center of gravity of the weight member at a central position in the head.
It is commonly felt that a downward swing, that is, a swing in which the head of the club is swung toward the ground, is advantageous because this type of swing gives a higher trajectory and backspin to the ball. This aids in stopping the ball immediately after it hits the ground. This type of swing is not applicable to other clubs such as drivers and fairway woods. At the bottom of the swing, the club head first contacts the ground at the central area of its sole or at an area slightly toward the heel. Subsequent to the contact with the ground, the club head is swung around as rotated around a shaft fixed to the heel portion of the club head.
A set of iron golf clubs usually consists of iron golf clubs of some ten types, including long irons, middle irons and short irons. It is a common belief that the long irons are difficult for ordinary amateur players to swing through with, and that the short irons tend to cause a pulling shot due to turn of the club head before impact.
Development of iron golf clubs has aimed at establishing a lower center of gravity in the head. Improving the rotational characteristics of the iron golf club head around its shaft has not been taken into consideration.